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Quantum Mechanics and Causality

Quiddity

UndertheInfluenceofGiants
I am a follower of aristotelian thomistic philosophy or best known as classical philosophy (most catholics are). I've managed to engage an atheist physicist who has already invoked the quantum theory to disprove the notion of causality. Given that I'm no physicist and at best lint on a great philosopher; I was hoping someone more aquainted with physics and classical philosophy could explain why he belives QM has officially made classical philosophy obsolete. So far as I can understand, quantum mechanics is able to disprove that certain things have a cause and therefore bringing the whole notion of causality into question. How exactly does it do this? I know it has to do with predictability but beyond that do I have to have a PhD in physics to know what the hell he is talking about?

I will note that he seems to lack understanding in classical philosophy. For example, for quantum mechanics to show us that nothing is responsible for anything is mind boggling to me. It may show us that there is nothing responsible for some things, but who doesn't already know that chance and luck play a part of the cosmos? You certainly don't need to be a physicist to know this. The absence of causes at one level does not prove there are no causes altogether. To think this somehow rattles the classical philosopher is only an indication of ignorance on the part of the phycist.

What am I missing? It's probably difficult to find someone who knows both discplines well enough to clarify?....:confused:
 

Skwim

Veteran Member
Not knowing how he's using QM to attack causality, I'm going to assume that it's the random nature of quanta that has convinced him that free will would be vindicated because determinism cannot hold up; absolutely random events lack a cause. But even if this was true, they would still fail to impinge on our world because we operate at a level (atomic) beyond the reach of quantum indeterminacy.

And, even if such randomness did influence how we act, it would effectively put our actions at the mercy of whatever randomness wrought, and not under our control. In effect, our will would be no freer under the randomness exemplified by quantum indeterminacy than it is under determinism.
 
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LegionOnomaMoi

Veteran Member
Premium Member
I am a follower of aristotelian thomistic philosophy or best known as classical philosophy (most catholics are). I've managed to engage an atheist physicist who has already invoked the quantum theory to disprove the notion of causality. Given that I'm no physicist and at best lint on a great philosopher; I was hoping someone more aquainted with physics and classical philosophy could explain why he belives QM has officially made classical philosophy obsolete.

There are two central challenges that modern physics introduced into philosophical accounts of causality. The first has to do with temporality and the classical conception of the arrow of time. Long before formal languages for logic (including modal logics, tense logics, etc.), Aristotle addressed the issue of the relationship between determinism and time. In De Interpretatione, he used the illustration of a sea battle. Basically, any proposition should (he thought) have a truth value. But this means that if I say "it will rain tomorrow" then this proposition is necessarily true or false. If it is true, then it must rain tomorrow, and vice versa if it is false. Either way, however, under one interpretation this implies fatalism.
These and similar issues involving time, fatalism, and determinism up until the 20th century were all based on the idea that time moved in one direction seperate from space. Spacetime changed this, and introduced a new problem for "fatalist" type arguments which does not depend on truth values of propositions. Spacetime involves reference frames. The greater the distance between two objects in the universe, the more drastic changes in "space" can effect location in spacetime. If we were seperated by a lightyear, but travelling in the same direction (I'm being informal and cavalier here for the sake of simplicity), one might say that we share the same temporal frame of reference. However, if you start moving away at an angle, your "now" could suddenly become centuries in the future or past relative to my "now" (backward or forward). If it is possible for your "now" to be centuries in my future, then everything which will happen in my future has already happened for you.

The second issue is QM itself, which is (again, under certain interpretions) inherently nonlocal. Correlations between quanta or particles occur instaneously no matter how far apart these particles are. In classical conceptions of causation, for one thing to "cause" another it must do so locally. If I shout "watch out!" at you, and you turn, I may be seperated by a certain distance but I can't cause you to react until soundwaves hit your eardrum and the movement of "hair" cells in your ear cause neurochemical reactions which generate electrical signals resulting in your perception of my shouting. So even though I may be 50 feet away, I only "caused" you to turn because of local interactions (i.e., you were able to hear my voice because it "travelled" to you).

However, nonlocal and instant correlations between spatially seperated particles radically challenge classical causation. How can these correlations exist, and what causes them? If interactions between particles can occur in "no-time" when they are lightyears away, how does this fit into classical causation?
 
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Meow Mix

Chatte Féministe
There are two central challenges that modern physics introduced into philosophical accounts of causality. The first has to do with temporality and the classical conception of the arrow of time. Long before formal languages for logic (including modal logics, tense logics, etc.), Aristotle addressed the issue of the relationship between determinism and time. In De Interpretatione, he used the illustration of a sea battle. Basically, any proposition should (he thought) have a truth value. But this means that if I say "it will rain tomorrow" then this proposition is necessarily true or false. If it is true, then it must rain tomorrow, and vice versa if it is false. Either way, however, under one interpretation this implies fatalism.
These and similar issues involving time, fatalism, and determinism up until the 20th century were all based on the idea that time moved in one direction seperate from space. Spacetime changed this, and introduced a new problem for "fatalist" type arguments which does not depend on truth values of propositions. Spacetime involves reference frames. The greater the distance between two objects in the universe, the more drastic changes in "space" can effect location in spacetime. If we were seperated by a lightyear, but travelling in the same direction (I'm being informal and cavalier here for the sake of simplicity), one might say that we share the same temporal frame of reference. However, if you start moving away at an angle, your "now" could suddenly become centuries in the future or past relative to my "now" (backward or forward). If it is possible for your "now" to be centuries in my future, then everything which will happen in my future has already happened for you.

The second issue is QM itself, which is (again, under certain interpretions) inherently nonlocal. Correlations between quanta or particles occur instaneously no matter how far apart these particles are. In classical conceptions of causation, for one thing to "cause" another it must do so locally. If I shout "watch out!" at you, and you turn, I may be seperated by a certain distance but I can't cause you to react until soundwaves hit your eardrum and the movement of "hair" cells in your ear cause neurochemical reactions which generate electrical signals resulting in your perception of my shouting. So even though I may be 50 feet away, I only "caused" you to turn because of local interactions (i.e., you were able to hear my voice because it "travelled" to you).

However, nonlocal and instant correlations between spatially seperated particles radically challenge classical causation. How can these correlations exist, and what causes them? If interactions between particles can occur in "no-time" when they are lightyears away, how does this fit into classical causation?

So a subject combining my two favorite subjects shows up after a long spell of posts that don't catch my interest, leading to my sabbatical, and you steal it from me in such a way that I can't even really add much that you didn't already say? The shame!
 

Quiddity

UndertheInfluenceofGiants
The difficult thing about this topic is that one inevitably branches out into all sorts of other topics that need to be clarified just to move an inch. For example, as a catholic, I don't subscribe to a libertarian view, or a determinist view, or even a compatbilist view. As Catholics we reject all three of those theories. To add, to us, cause and effect isn't something that trickles all the way to the beginning or that only effects necessary things.
 

Quiddity

UndertheInfluenceofGiants
So a subject combining my two favorite subjects shows up after a long spell of posts that don't catch my interest, leading to my sabbatical, and you steal it from me in such a way that I can't even really add much that you didn't already say? The shame!

Leave with this for you to read:

Edward Feser: Oerter contra the principle of causality

So far as I can tell, Phycists trying to make causality obsolete have some misunderstandings that need to be cleared up. In short, for quantum mechanics to show us that nothing is responsible for anything is mind boggling imo. It may show us that there is nothing responsible for some things, but who doesn't already know that chance and luck play a part of the cosmos? You certainly don't need to be a physicist to know this. The absence of causes at one level does not prove there are no causes altogether. To think this somehow rattles the classical philosopher is only an indication of ignorance on the part of the phycist. Let me know what you think. I'd be really interested in your opinion.
 

LegionOnomaMoi

Veteran Member
Premium Member
So a subject combining my two favorite subjects shows up after a long spell of posts that don't catch my interest, leading to my sabbatical, and you steal it from me in such a way that I can't even really add much that you didn't already say? The shame!
I waited as long as I could, I swear! (also, I've no doubt you could say more with less)
 

LegionOnomaMoi

Veteran Member
Premium Member
So far as I can tell, Phycists trying to make causality obsolete have some misunderstandings that need to be cleared up. In short, for quantum mechanics to show us that nothing is responsible for anything is mind boggling imo.

Some comments:

1) Physicists are not "trying to make causality obsolete." Rather, the nature of philosophical discussions about causation has changed.
2) There is not now, nor has there ever been a single agreed notion of causation. Philosophers and theologians have debated the concept for millenia.
3) "Responsible for" and "caused" are not really synonymous from a philosophical point of view. The former carries connotations unfit for theories of causation (a legal guardian may be responsible for their charge, but they did not "cause" that individual).
4) There's a reason Einstein so disliked the idea of "spooky action at a distance". After centuries of classical mechanics, which were predated by more intuitive but still related ideas about the nature of time, space, motion, etc., relativity and QM radically challenged not only long-held views about the structure of the cosmos, but also human experience and intuition. The fact that it boggles the mind, therefore, is hardly suprising.
 

Meow Mix

Chatte Féministe
Leave with this for you to read:

Edward Feser: Oerter contra the principle of causality

So far as I can tell, Phycists trying to make causality obsolete have some misunderstandings that need to be cleared up. In short, for quantum mechanics to show us that nothing is responsible for anything is mind boggling imo. It may show us that there is nothing responsible for some things, but who doesn't already know that chance and luck play a part of the cosmos? You certainly don't need to be a physicist to know this. The absence of causes at one level does not prove there are no causes altogether. To think this somehow rattles the classical philosopher is only an indication of ignorance on the part of the phycist. Let me know what you think. I'd be really interested in your opinion.

Interesting paper. The physicist he's discussing with is very correct on one matter -- that Bell's inequalities rule out the notion that there are hidden variables or missing pieces of information that could explain the apparent causeless events in some quantum mechanical systems.

Also, the analogy the blogger makes between Bell's theorem and Kepler's laws is interesting; but ultimately (though understandably) misses the point a little: he points out that Kepler's lack of explanation for why the orbits planet the way they do doesn't mean there isn't one; but that's exactly what Bell's inequalities do show for quantum systems: that there is a lack of explanation in principle, in any sense, involving local explanations.

Basically, either scientific realism (the notion that our methods are describing/correlating to something real -- parenthetical explanations mostly for layman readers) or locality must be abandoned -- in fact, some even suggest (e.g. Bernard d'Espagnat, Roland Omnes, others) multitudinism must be abandoned (which is a stronger consequence of dropping locality -- multitudinism is the notion that "things" are separate from one another at all; though non-multitudinism can give the macroscopic illusion of separation).

To make the analogy work better, there would have to be something about Kepler's laws which demonstrated in principle that not even other objects could explain why planets follow a certain shape in their orbits -- or something.

However, despite all this, I am in fact in agreement that Aristotlian logic is the only ontological logic (i.e. that can describe reality -- so-called "alternative logics" do have a place in describing doxastic revision and decision making in epistemically deficient systems and such, but they cannot describe ontological things in terms of existence). I'm also a staunch realist.

QM does force us to abandon the notion of locality, but I don't think that's a big deal. I agree that it doesn't devastate causality; but it might cripple some of our intuitive thoughts about causality.

By far and large, physicists have opted to abandon scientific realism over locality when they could -- that's entirely what the Copenhagen Interpretation was all about. Realism is starting to make a comeback (laregely thanks to Roland Omnes and the notion of quantum decoherence), but it doesn't appear as though locality will ever quite be the same again.

Again, though, that doesn't damage the basic notion of causality -- just some of our intuitions about causality. This is a long winded way of me saying that I agree with your assessment insofar as I understand your position; but also warning you not to undervalue the force of the opponent's argument because the opponent is technically correct about locality -- just not strictly correct that it undermines causality.
 
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Quiddity

UndertheInfluenceofGiants
Interesting paper. The physicist he's discussing with is very correct on one matter -- that Bell's inequalities rule out the notion that there are hidden variables or missing pieces of information that could explain the apparent causeless events in some quantum mechanical systems.

Also, the analogy the blogger makes between Bell's theorem and Kepler's laws is interesting; but ultimately (though understandably) misses the point a little: he points out that Kepler's lack of explanation for why the orbits planet the way they do doesn't mean there isn't one; but that's exactly what Bell's inequalities do show for quantum systems: that there is a lack of explanation in principle, in any sense, involving local explanations.

Basically, either scientific realism (the notion that our methods are describing/correlating to something real -- parenthetical explanations mostly for layman readers) or locality must be abandoned -- in fact, some even suggest (e.g. Bernard d'Espagnat, Roland Omnes, others) multitudinism must be abandoned (which is a stronger consequence of dropping locality -- multitudinism is the notion that "things" are separate from one another at all; though non-multitudinism can give the macroscopic illusion of separation).

To make the analogy work better, there would have to be something about Kepler's laws which demonstrated in principle that not even other objects could explain why planets follow a certain shape in their orbits -- or something.

However, despite all this, I am in fact in agreement that Aristotlian logic is the only ontological logic (i.e. that can describe reality -- so-called "alternative logics" do have a place in describing doxastic revision and decision making in epistemically deficient systems and such, but they cannot describe ontological things in terms of existence). I'm also a staunch realist.

QM does force us to abandon the notion of locality, but I don't think that's a big deal. I agree that it doesn't devastate causality; but it might cripple some of our intuitive thoughts about causality.

By far and large, physicists have opted to abandon scientific realism over locality when they could -- that's entirely what the Copenhagen Interpretation was all about. Realism is starting to make a comeback (laregely thanks to Roland Omnes and the notion of quantum decoherence), but it doesn't appear as though locality will ever quite be the same again.

Again, though, that doesn't damage the basic notion of causality -- just some of our intuitions about causality. This is a long winded way of me saying that I agree with your assessment insofar as I understand your position; but also warning you not to undervalue the force of the opponent's argument because the opponent is technically correct about locality -- just not strictly correct that it undermines causality.
I wasn't undervaluing it, I just didn't understand why this was being used by this gentleman to bring down the very foundation of causality. Naturally, that is going to get my attention. As alluded to before, causes don't have to produce a single determinate effect. To both Aristotle/Thomas there is such a thing a thing as chance, contingency in nature, etc. In fact, most causes are contingent not necessary. In that sense, it did very little to causality. Given also that he considers himself a hard line empericist, I took his words in such context.
 

Quiddity

UndertheInfluenceofGiants
1) Physicists are not "trying to make causality obsolete." Rather, the nature of philosophical discussions about causation has changed.
No qualms here.
2) There is not now, nor has there ever been a single agreed notion of causation. Philosophers and theologians have debated the concept for millenia.
It's philosophy, we argue about everything. :D Having said that, classical philosophers, so far as I know have had a general agreement about what causation is, but like most things, when you get into all the details some disagreement arises.
3) "Responsible for" and "caused" are not really synonymous from a philosophical point of view. The former carries connotations unfit for theories of causation (a legal guardian may be responsible for their charge, but they did not "cause" that individual).
"Caused" works just fine. I don't always wear my philosopher hat when choosing words. Thanks for pointing that out.
4) There's a reason Einstein so disliked the idea of "spooky action at a distanc=LegionOnomaMoi;3034040e". After centuries of classical mechanics, which were predated by more intuitive but still related ideas about the nature of time, space, motion, etc., relativity and QM radically challenged not only long-held views about the structure of the cosmos, but also human experience and intuition. The fact that it boggles the mind, therefore, is hardly suprising.
Shall I say "ludricous" instead?
 
I am a follower of aristotelian thomistic philosophy or best known as classical philosophy (most catholics are). I've managed to engage an atheist physicist who has already invoked the quantum theory to disprove the notion of causality. Given that I'm no physicist and at best lint on a great philosopher; I was hoping someone more aquainted with physics and classical philosophy could explain why he belives QM has officially made classical philosophy obsolete. So far as I can understand, quantum mechanics is able to disprove that certain things have a cause and therefore bringing the whole notion of causality into question. How exactly does it do this? I know it has to do with predictability but beyond that do I have to have a PhD in physics to know what the hell he is talking about?

I will note that he seems to lack understanding in classical philosophy. For example, for quantum mechanics to show us that nothing is responsible for anything is mind boggling to me. It may show us that there is nothing responsible for some things, but who doesn't already know that chance and luck play a part of the cosmos? You certainly don't need to be a physicist to know this. The absence of causes at one level does not prove there are no causes altogether. To think this somehow rattles the classical philosopher is only an indication of ignorance on the part of the phycist.

What am I missing? It's probably difficult to find someone who knows both discplines well enough to clarify?....:confused:

Doesn't seem relevant. Why do you ask? The idea is a theory. Why? It is an explanation. If general, it is perhaps an explanation looking at a minute particle, perhaps.
 
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